Since conventional numerical control equipment (NC) is arranged so that when a group of commands (micro instructions) for performing a certain operation, is made programmable in the form of a single command (a macro instruction), and a program for converting the single command to the group of commands is stored in a ROM or the like of the NC (as is the case with an ordinary cutting program), it is difficult to make the NC versatile. That is to say, the contents of the above conversion program usually differ with machine tools, so it is necessary to modify the specifications of the NC system for each machine tool to which the NC is connected. Furthermore, the situation occasionally arises where it would be desirable, from the standpoint of a machine tool maker, to change the conversion program for their own purposes with a view to presenting their own characteristic feature. However, such a change is not always easy with the prior art numerical control equipment, as mentioned above.